Boku ga Mitakatta Aozora to release the fourth single. The limited edition type B includes new songs by Aozora Gumi and Kumo Gumi. Comes with a Blu-ray with music video(s) for new song(s) by the 4th Kumo Gumi, making-of, and a bonus video (2), an application card (valid only in Japan), and a trading card (B) randomly selected from 23 kinds.